Your First Python Program

If Statements: Making Decisions

• Programs need to make decisions based on conditions:
• “`python
• age = 20
• if age >= 18:
• print('You are an adult')
• else:
• print('You are a minor')
• “`
• Important: Python uses indentation (4 spaces) instead of brackets!

Elif: Multiple Conditions

• When you have more than two options:
• “`python
• marks = 85
• if marks >= 90:
• print('Grade: A+')
• elif marks >= 80:
• print('Grade: A')
• elif marks >= 70:
• print('Grade: B')
• else:
• print('Grade: C')
• “`

For Loops: Repeating Tasks

• Repeat actions a specific number of times:
• “`python
• for i in range(5):
• print('Hello', i)
• “`
• This prints 'Hello' 5 times (0 to 4).
• Loop through a list:
• “`python
• fruits = ['apple', 'banana', 'mango']
• for fruit in fruits:
• print(fruit)
• “`

While Loops: Repeat Until Condition

• Keep repeating as long as a condition is true:
• “`python
• count = 1
• while count <= 5:
• print(count)
• count = count + 1
• “`
• This prints numbers 1 to 5.

Real Example: Calculator Program

• “`python
• num1 = float(input('Enter first number: '))
• num2 = float(input('Enter second number: '))
• operation = input('Enter operation (+, -, *, /): ')
• if operation == '+':
• result = num1 + num2
• elif operation == '-':
• result = num1 – num2
• elif operation == '*':
• result = num1 * num2
• elif operation == '/':
• result = num1 / num2
• else:
• result = 'Invalid operation'
• print('Result:', result)
• “`